The pinyon trees at Natural Bridges National Monument were laden with seeds, which are not technically nuts. I also passed many juniper trees as I walked. We tend to lump the two species together into “P-J” vegetation, but they're quite different. Pinyons have needles and pine cones, like Christmas trees (on the right in the photo). Juniper trees (left) are covered with prickly scales and purple juniper berries, although these are technically cones, too.
Last fall was the first time I saw pinyon nuts on the trees. The smooth, elegant seeds inside the flared cones reminded me of the complexity of ecological relationships and the diversity of our ecological knowledge.
Four Corners, 1993
In the spring of 1993, a healthy young couple got sick and died in the Four Corners area. What they thought was the flu quickly turned into deadly respiratory distress. When the young woman died, it was a heartbreaking, isolated incident. When her fiancé died a few days later, researchers started looking for a killer.
Investigators found five other healthy young people who had died suddenly. Each was found to have been infected with a previously unrecognized Hantavirus, now called Sin Nombre virus (SNV, “No Name Virus”). The same virus was later found in tissues saved from people who had died of unexplained lung disease dating back to 1959.
Ironically, it’s not the virus itself that destroys the lungs. The body's immune system overreacts and attacks the tiny blood vessels in the lungs, with deadly results.
The first Hantavirus was described in Korea in the early 1950s. All of the known Hantaviruses all are carried by rodents. Researchers were able to pinpoint deer mice (Peromyscus maniculatus) as the carrier of SNV.
Why did SNV erupt in 1993?
Researchers found answers in both modern climate science and traditional ecological knowledge from the Four Corners area and the Pacific coast of South America.
The winter of 1991-1992 was an El Niño winter; it was wetter than usual in the U.S. Southwest. Plants used the extra water to grow vigorously the next summer. Insects thrived on the lush vegetation and laid masses of eggs. The plants and trees, including pinyons, produced large crops of seeds at the end of the summer.
Deer mice, one of the most common rodents in North America, feasted on the insects and seeds. The mice raised extra litters and stored the plentiful seeds for the coming winter. By the next spring, there were so many mice that it was impossible for people to avoid crossing paths with them. Some of the mice carried SNV.
Farmers and fishers in Peru and Bolivia recognized the El Niño weather pattern centuries ago. This periodic warming of the eastern Pacific decimates anchovy and sardine catches and dumps record rainfall on parched lands. Farmers in the area traditionally predict El Niño events by the brightness of stars in the Pleiades.
People living in the Four Corners area recognized previous eruptions of disease after wet years and linked the outbreaks to mice. Now that climate science recognizes the El Niño Southern Oscillation, we know that the previous outbreaks corresponded with El Niño winters.
Beyond Citizen Science
Pinyon nuts and Hantavirus reminded me how often we overlook nonscientists’ ecological knowledge. Although researchers value citizen scientists for routine tasks, the same professionals ignore nonscientists’ problem-solving skills and unique knowledge.
Citizen scientists provide eyes and ears to collect data that can’t be automated. Amateur birders have assembled over a century of data on bird population trends across the country for the Audubon Society’s Christmas Bird Count. Citizen observers record seasonal changes in plants and animals for the National Phenology Network. These data help climate scientists predict how plants and animals will respond to changing climates. Machines can automatically record temperature, wind speed, and humidity, but they can’t watch for the first maple leaves in New England or spot the first robin to return to Minneapolis.
People are also better than computers at seeing patterns in data and images. Although we couldn’t handle the terabytes, petabytes, then exabytes of information without computers, the machines can’t do everything. Citizen scientists comb through NASA data to spot the small anomalies in the brightness of distant stars that indicate the presence of undiscovered planets. People are also better than computers at categorizing images. When researchers asked for help classifying one million galaxies by shape, 150,000 citizen scientists completed the work in three weeks.
Nonscientists excel in research tasks where a willingness to follow directions and a high tolerance for boredom are more important than academic training (which describes most of the work in research). But, when it comes to the developing a list of hypotheses--possible explanations for the mysteries of the universe--you'd better have "M.S." or "Ph.D." after your name.
Tapping the Ecological Knowledge of Nonscientists
Residents of the Four Corners area recognized that disease outbreaks can be linked to wet winters and deer mice. These citizen scientists made observations and discovered a pattern. Although our innate drive to see patterns can sometimes lead us astray (our “lucky” shirt, or our “system” for winning at penny slots), this urge is the basis of science. When we understand cause and effect in the past, we can predict what will happen in the future.
When my friends Jake Weltzin and Steve Archer studied mesquite trees spreading into grasslands, they asked the local ranchers why the vegetation was changing. These researchers tested the ranchers’ hypothesis and found that prairie dogs play a key role in keeping mesquite out of grasslands. Their report, published in the scientific journal, Ecology, said: “This research was the product of discussions with historians and ranchers G. D. and Guy London (born in the early 1900s), who proposed to us that increases in mesquite abundance on their ranch were initiated ‘after we killed all the prairie dogs.’”
When more than a thousand square miles of weedy cheatgrass vanished across in the Intermountain West several years ago, I wanted to know why. I stopped and asked at a ranch next to one of the large bare areas. The rancher told me he had seen army cutworms eating every emerging plant one night (the researchers were all at home at that late hour). Several entomologists laughed when I told them the story, but their colleagues who had also caught the insect larvae in the act didn’t laugh.
A botanist taught me how to recognize Phaseolus--common bean--plants in southern Mexico: Pull off a set of the plant's three leaflets and press them onto your shirt. If the leaves “velcro” themselves to your clothing, you've found Phaseolus and won a bean leaf cluster.
A recent article in the New York Times described how this traditional knowledge could be brought indoors to combat an old plague that’s making a comeback in the U.S. The same hairs that stuck to my shirt also ensnare bed bugs.
I see a pattern here: when researchers ask people how the natural world works, nonscientists can come up with sound hypotheses. When researchers test these hypotheses with careful experiments, the same way they test their own ideas, we add to the body of scientific knowledge and understand our world better.
Researchers, let’s remember to tap the ecological knowledge of nonscientists. They watch and learn the same way scientists do.